[Seaside] Re: Are Collections threadsafe?

Andreas Raab andreas.raab at gmx.de
Wed Feb 27 01:30:54 UTC 2008

goran at krampe.se wrote:
> I didn't imply the problems have been undetected - I just meant that
> they have gone undetected for a looong time. And most users deploy stuff
> with Squeak and do just fine. That is all I am saying.

The real trouble is that some of the people (like Philippe) that are 
closest to the point of the problem end up complaining in general 
instead of gathering valuable data. Basically it's all flawed logic of 
the form "clearly, our code can't possibly be wrong so the VM must be 
broken and why don't you guys just get your act together and fix it".

What people *really* need to do in such a situation is to gather as much 
data as possible. If you can still save the image, save it. If you can 
still get a bunch of stack traces, get them. Attach gdb to the VM and do 
a printAllStacks() - this is probably the most important information you 
get in a situation like this (at Qwaq, we have hooked this up to a USR1 
signal so that when we need to restart the servers we first get a full 
stack trace and then restart the images just in case).

Once you have gathered all that information, post it to Squeak-dev. 
There are actually people out there who care about it. They just don't 
care very much about editorial comments of the form "TEH SQUEAK SUCKZ!". 
If you want a solution, then provide the input that helps other people 
resolving your problem. The short form of that equation is:
   complaints == no data
   no data == no solution
And if you keep this in mind (and your frustration to a minimum) you 
will likely find that *with* data the probability of actually fixing 
your problems goes up dramatically.

> Of course we should fix it. But we should also not scare people into
> thinking that Semaphores are *totally* broken and that Squeak is total
> crap when it comes to concurrency. :)

Absolutely. At Qwaq, we routinely run servers with hundreds of 
concurrent connections piping through gigabytes of data per day.

   - Andreas

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